Fluid mover



D. F. WHITE FLUID MOVER April 12, 1966 Filed Aug. 1'7, 1964.

AT TORNEY United States Patent 3,245,611 FLUID MOVER Douglas F. White, Bedminster, N.J., assignor to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Delaware Filed Aug. 17, 1964, Ser. No. 390,084 4 Claims. (Cl. 230-134) This invention pertains-to the moving of fluid and more particularly to centrifugal fluid movers.

Centrifugal means for moving fluids such as air, gases or liquids take many forms such as pumps, fans, blowers and compressors. When such means are used particularly for fans and diffusers their efliciency depends on th rang ot operating speeds. If the centrifugal impeller rotates too slowly, the efiiciency of fluid movement is low. As the rotational speed of the impeller increases, the efficiency of the fluid movement by the impeller increases. However, unfortunately, the noise generated by the interaction ofthe impeller and the fluid also increases. When the fluid mover is to .be employed as an air diffuser or a fan the generated noise can be an annoyance. v This is particularly so when the fan is close to peoplewhich is the most usual case.

There have been proposals toutilize the shear-force pumping principle in fluid movers such as fans. While such devices have admirable noise and other characteristics, they have a maximum rotor or impeller efficiency of approximately sixty percent. In addition, at very low discharge rates there is the possibility of reverse fluid flow.

It is, accordingly, a general object of the invention to provide an improved centrifugal fluid mover of the type having an axial intake and a peripheral discharge.

It is another object of the invention to provide a centrifugal fluid mover of improved efliciency over a broad range of fluid flow rates.

It is a further object of the invention to provide a relatively quiet fluid mover which can move considerable quantities of fluid.

It is yet another object of the invention to provide an improved method of more efliciently and reliably moving fluid.

Briefly, the invention contemplates the movement of fluid by guiding the fluid axially along a path, centrifugally impelling the fluid radially outward from the axial path and imparting to the radially outward impelled fluid a shear force to super-impose an added tangential component of velocity to the centrifugally impelled fluid.

According to a feature of the invention, there is provided an impeller comprising a plurality of axially extending and circumferentially displaced blades positioned to define substantially a hollow cylinder. There is a plurality of annular members. Each of the annular members lies in a plane which is transverse to the axis of the cylinder. The annular members are fixed to the blades.

It should be noted that by the use of annular members fixed to the blades the velocity of the fluid moving from the blades is evened out and the usual peripheral distortions of the velocity of the moving fluid are minimized.

Other objects, features and advantages of the invention will be apparent from the following detailed description when read with the accompanying drawings wherein:

FIGURE 1 shows a perspective view of a fluid mover in accordance with the invention wherein a shroud encloses a rotatable impeller;

FIGURE 2 shows an end view of the fluid mover 0 FIGURE 1 including a motor for rotating the impeller; FIGURE 3 shows an axial section of the impeller of FIGURES 1 and 2;

FIGURE 4 is a view taken along the lines 4-4 of "ice FIGURE 3 showing the basic cross-section of the impeller according to a feature of the invention; and

FIGURE 5 is a diagram showing three different types of blades and their respective exit angles.

Referring now to the drawings, there is shown a double inlet fluid mover comprising a housing or shroud 12 enclosing a rotatable impeller 14 which is driven by motor 16. Motor 16 is connected to housing 12 by standoffs 15. Although a motor 16 is shown for rotating impeller 14, conventional pulley and belt drives can be used with similar success. As the impeller 14 rotates, fluid is axially guided into the housing 12 via axial inlet 18 and is circumferentially driven from outlet'20.

Impeller 14 includes two annular end plates 22 and 24 and a spoked driving plate 26. Each of the plates 22, 24 and 26 has a plurality of radial slots that are slightly arcuate to support blades 28. The blades 28 are elongated striplike elements of arcuate cross section which extend parallel to the axis of the impeller 14. As can be seen in FIGURES 3 and 4, blades 28 are generally parallel to and spaced from each other. Blades 28 substantially define a hollow cylinder with the array of blades 28 and end plates 22 and 24 resembling a squirrel cage. Extending from blades 28 are a plurality of annular members in the form of apertured discs 30. The inner edges of discs 30 are fixed to the outer edges of blades 28. The discs 30 are mutually spaced and lie in planes transverse to the axis of impeller 14. The discs are sufficiently thick and made of such material so as to supply structural rigidity. Discs 30 are axially spaced from each other by preferably one-fifteenth to onetwentieth of the rotor intake diameter D. In addition, the outer diameter of discs 30 is preferably no more than one and one-half times greater than the inner diameter of discs 30.

Spoked plate 26 is fixed to shaft 32 which is connected to motor 16 to rotationally drive impeller 14. Plate 36 has fixed thereto setotfs 15 for supporting motor 16.

During operation, when impeller 14 is rotating, fluid enters via axial inlet 18 into the hollow cylinder defined by blades 28. The fluid is centrifugally driven radially outward over blades 28, which impart a circumferential and radial motion to the fluid. As the fluid enters the region between the discs 30, the fluid is further tangentially accelerated because of the shear force generated by the slip between the surfaces of discs 30 and the fluid. The fluid then passes radially beyond the gap between the discs 30 into the region where housing 12 defined outlet 20. By virtue of the tangential components of velocity, the fluid is propel-led from outlet 20.

Impeller 14 can employ various types of blades. FIG- URE 5 shows the profiles of the various blade types. In particular, impeller 14 can use Sirocco type B1, radial tip type 132 and backward curved type B3. It has been found that the blade exit angle has a decided effect on the efficiency. The blade exit angle is defined as the angle between the tangent to the circle swept out by the blade tip, and the projected extension of the blade tip. The angle is measured in the direction of blade movement. For ex ample, in FIGURE 5, when the impeller is rotating in a clockwise manner, the blade exit angle A1 of blade B1 is the angle measured clockwise between the tangent T1 and the projected extension E1. Similarly, blade B2 has an exit angle A2 between the tangent T2 and the projected extension E2; and blade B3 has an exit angle A3 between tangent T3 and projected extension E3. It has been found that efficient operation is obtained with blade exit angles of from 70 to 140 degrees and peak efficiency occurs as the angle approaches degrees.

There has thus been shown an improved fluid mover which byrhavinga plurality of annular members fixed to the blades of a centrifugal impeller increases the pressure head at the low-flow end of the pressure flow characterist-ieof the usual devices as well as prevent-ing t-he possibility of reverse flow at very low discharge rates.

While only one embodiment of the invention has been shown and described in detail, there will now be obvious to those skilled in the art many modifications and variations of the invention such as blowers, pumps and compressors. However, these and other variations which while gaining the advantages of the invention will not depart from the spirit thereof as defined in the appended claims.

What is claimed is:

. 1. An impeller of the single stage double intake type comprising a central radially extending annular driving plate, an annular bank of axially extending blades extending in opposed axially direction on each side of said driving plate and radially inwardly of the periphery of said driving plate, said blades having radially inner axially extending leading edges to define an annular vaneless intake chamber about the axis of said disc, and trailing edges spaced radially outwardly from said leading edges,

an annular plate mounted on the ends of said blades axially spaced from, said central driving plate defining a central intake and extending radially outwardly of said trailing edges to define with said driving plate an annular chamber of substantial size, havinga radial depth substantially greater than the radial depth of said blades,

4 a plurality of flat axially spaced discs joined to the trailing edges of each bank of said axially extending blades and extending radially outwardlyto a diameter substantially equal to the diameter of said driving plate; said driving plate, said annular plates and said axially spaced discs cooperating to engage the fluid impelled by the blades and to energize the same outwardly of the trailing edges of the blades. a

2. The combination of claim 1 wherein said axially extending blades are of the Sirocco type;

3. The combination of claim 1 wherein said axially extending blades are of the radial tip type. i

4. The combination of claim 1 wherein said axially extending blades are of the backward curved type.

References Cited bythe Examiner UNITED STATES PATENTS 1,154,152 9/1915 Williams 230 127 FOREIGN PATENTS. 1,280,348 11/1961 France.

Examiners 

1. AN IMPELLER OF THE SINGLE STAGE DOUBLE INTAKE TYPE COMPRISING A CENTRAL RADIALLY EXTENDING ANNULAR DRIVING PLATE, AN ANNULAR BANK OF AXIALLY EXTENDING BLADES EXTENDING IN OPPOSED AXIALLY DIRECTION ON EACH SIDE OF SAID DRIVING PLATE AND RADIALLY INWARDLY OF THE PERIPHERY OF SAID DRIVING PLATE, SAID BLADES HAVING RADIALLY INNER AXIALLY EXTENDING LEADING EDGES TO DEFINE AN ANNULAR VANELESS INTAKE CHAMBER ABOUT THE AXIS OF SAID DISC, AND TRAILING EDGES SPACED RADIALLY OUTWARDLY FROM SAID LEADING EDGES, AN ANNULAR PLATE MOUNTED ON THE ENDS OF SAID BLADES AXIALLY SPACED FROM SAID CENTRAL DRIVING PLATE DEFINING A CENTAL INTAKE AND EXTENDING RADIALLY OUTWARDLY OF SAID TRAILING EDGES TO DEFINE WITH SAID DRIVING PLATE AN ANNULAR CHAMBER OF SUBSTANTIAL SIZE, HAVING A RADIAL DEPTH SUBSTANTIALLY GREATER THAN THE RADIAL DEPTH OF SAID BLADES, A PLURALITY OF FLAT AXIALLY SPACED DISCS JOINED TO THE TRAILING EDGES OF EACH BANK OF SAID AXIALLY EXTENDING BLADES AND EXTENDING RADIALLY OUTWARDLY TO A DIAMETER BLADES AND EQUAL TO THE DIAMETER OF SAID DRIVING PLATE; SAID DRIVING PLATE, SAID ANNULAR PLATES AND SAID AXIALLY SPACED DISCS COOPERATING TO ENGAGE THE FLUID IMPELLED BY THE BLADES AND TO ENERGIZE THE SAME OUTWARDLY OF THE TRAILING EDGES OF THE BLADES. 